Download Saclay Drift Chambers - Operating instructions

d. Close the MM/DC ethane valve in flammable gas arrival rack (if MMs detectors have
also been prepared for this operation).
e. Purge completely all 3 chambers with Argon : changing 4 times the chamber volumes
takes 5 days for DC0/DC1 and 14 days for DC4.
4. Operation
a. DCs gas flows and mixtures are controlled by PLC3 and by the bubblers in the
MM/DC gas rack.
b. DCs High Voltage and threshold settings are controlled by the COMPASS slow
control. For Slow Control commands go in the Saclay barrack.
c. Check the 3 DC bubblers twice per shift. Normal bubbling is in the range: 0.3-0.6 Hz.
5. PLC3 operation
a.
b.
c.
d.
e.
f.
On the touch screen: select DC
Push the MENU button
Push the R4 box in order to enter the password.
Type the password: 6535 and then push ENTER.
Push the ESC button
Select the R1 button (Ethane proportion). This proportion is either 0 (no flammable
gas) or 45 (during data taking). Note: equalizing the fluxes may need to slightly
change the 45% value.
g. Change also the CF4 proportion (if needed).
h. Push the ESC button and check that the both Ar and Ethane flows are equal. If not
adjust the Ethane proportion 45%±2%